.{$tree-prefix}
  .{$tree-prefix}-list
    .{$tree-prefix}-item
      padding 4px 0 0
      .{$tree-prefix}-item-expand
        display inline-block
        width 18px
        text-align right
        color $gray2-color
        cursor pointer
        transition all .2s cubic-bezier(0,1,0,1)
        > i
          transform scale(0.9)
          &:hover
            color $primary-color
      > .{$tree-prefix}-list
        overflow hidden
        max-height 0
        transition max-height .2s cubic-bezier(0,1,0,1)
        margin-left 18px
      &.{$tree-prefix}-item-opened
        > .{$tree-prefix}-list
          max-height 10000px
          transition max-height 2s ease-in-out
        > .{$tree-prefix}-item-expand
          transform rotate(90deg)
          position relative
          top -2px
      &.{$tree-prefix}-item-selected
        > .{$tree-prefix}-item-desc
          background-color $primary-color
          color $white-color
      .{$tree-prefix}-item-icon
        display inline-block
        width 18px
        text-align left
      .{$tree-prefix}-item-desc
        display inline-block
        padding 0 3px
        cursor pointer
        border-radius $border-radius-size
        &:hover
          background-color $gray3-color
